Quick Tour

Basics | Basic Input Frame | Calculation of Sun Position and Radiation | Display on Desktop | Tour: Create a 3d Scene

Calculation of Sun Position and Radiation

In order to calculate the sun position and the solar radiation choose the function Basic data on sun position. The output frame on the right half looks then like this:

Output frame


In the top line the current sun position is displayed both graphically and by numbers:

Furthermore, the global radiation (solar radiation including the diffusive sky radiation upon a horizontal plane) and the annually accumulated energy coming from the global radiation is displayed on the right side.

Twilight Phases and Sunrise and Sunset

In the following table the times of the sunrise, sunset, and the begin and end of different twilight phases are displayed. Furthermore the length of the day (including the corresponding twilight phase) and the length of the night (excluding the corresponding twilight phase) are displayed.

The twilight phases are defined as follows:

Yearly Overview

The diagram under Overview Sun Position / Radiation shows an overview of the sun position during one year.

One day corresponds to a vertical line where the altitude of the sun is displayed starting from 0:00 at the bottom end until 24:00 at the top end.

White spots correspond to an sun altitude of more than 45° above the horizon. The different twilight phases are denoted by the colors orange (civil t.), blue (nautical t.), and grey (astronomical t.).

The diagram above shows the sun position for Munich. The variation of the day length during the year is evident. The discontinuities in the diagram come from switching to and from the daylight saving time in spring and autumn.

The green cursor is located at the current date and time. It can be dragged with the mouse to an arbitrary position, at which all calculations are continuously updated.

Global Radiation

By clicking on the radio button Global Radiation an overview of the global radiation is displayed:

Output frame global radiation

The legend can be edited. By clicking on the legend the following editor window is shown:

Edit legend

Each color can be edited by clicking on it. In the text fields the corresponding values can be edited. The button Default values restores the original settings.

Radiation at Sample Points

If the 3d scene contains sample points, an overview of the radiation at each sample point can be displayed. Periods during which the sample point lies in the shadow can be marked with a different color. In the table below the energy output of a photovoltaic solar power plant located at the sample point considering the shadow is displayed (for each season separately and for the whole year).

This topic is explained in detail in the chapter (Tour: Create a 3d Scene).

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